Generating random string in PHP: how to do it correctly and securely?

Hello everyone! I'm a beginner in PHP and writing a small website. I need to generate random strings for session tokens, temporary passwords, and link identifiers. I found this code on the internet: ```php function generateRandomString($length = 10) { $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'; $charactersLength = strlen($characters); $randomString = ''; for ($i = 0; $i < $length; $i++) { $randomString .= $characters[rand(0, $charactersLength - 1)]; } return $randomString; } ``` But I'm concerned about several things: 1. The `rand()` function — I've heard it's not very random. 2. If I need 1000 strings, the script runs slowly. 3. I don't know if this is suitable for cryptographic purposes (tokens). Can I use th